Thesis (Ph.D.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Laser Application in Engineering

The design of practical combustion system must ensure a flexible range of operating condition and comply with the increasingly tighter pollution restrictions. Partially premixed flames, defined as flames where the mixture is inhomogeneous and varies from fuel-rich to stoichiometry and fuel-lean, are found in many engineering applications. In modern internal combustion engines, using multiple injections of fuel to control emissions, partially premixed environment is typically formed before ignition. The aim of this work is to present a comprehensive study for the effect of coflow on the flame stability of partially premixed Propane flames in a concentric flow conical nozzle (CFCN) burner. Also, structure and flow field of some selected cases are presented using high-speed Stereoscopic Particle Image Velocimetry, SPIV, plus OH Planar Laser-Induced Fluorescence, OH-PLIF, followed by Simultaneous PIV/OH-PLIF. In addition, the effects of the mixing fields on the structure and stability of partially premixed NG flames. The flame stability is first mapped then the mixing field in a concentric flow conical nozzle (CFCN) burner with wellcontrolled mechanism of the mixing is investigated using Rayleigh scattering technique. The experimental data of the mixing field cover wide ranges of Reynolds numbers, equivalence ratios and mixing lengths

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